1. Field of the Invention
The present invention relates to a substrate holding device, a lithography apparatus using the same, and a device manufacturing method.
2. Description of the Related Art
A semiconductor manufacturing apparatus such as an exposure apparatus exemplified by a lithography apparatus includes a substrate holding device for holding a substrate to be treated. In general, the substrate holding device includes a vacuum adsorption chuck having an adsorption surface for adsorbs and holding a substrate, a vacuum port formed on the chuck, and a pressure sensor that monitors pressure of an exhaust port connected to the vacuum port. In this case, when the measurement value of the pressure sensor indicates any value (vacuum state) after the adsorption of a substrate placed on the chuck, the substrate holding device determines that the substrate is adsorbed and held. On the other hand, when the adsorption of the substrate is stopped and the pressure in the exhaust port is returned to substantially atmospheric pressure, the substrate holding device determines that the substrate-held state is released.
Here, a substrate to be treated may be placed on the chuck with its surface distorted or warped due to thermal treatment or pressure treatment during various manufacturing processes. In addition, an anomaly such as dust attachment, scratch, or the like may occur on the back side of a substrate to be treated (or the resting surface of the chuck). In order to cope with these anomalies, Japanese Patent Laid-Open No. 2004-140071 discloses a substrate holding device that adsorbs a substrate with high accuracy by providing a plurality of pin-like protrusion arrangements on the adsorption surface. Also, Japanese Patent Laid-Open No. 10-70069 discloses a dust detection device that detects the presence or absence of dust and the position of dust, when any dust is present between the substrate and the chuck, so as to clean more intensively based on its detection result. Furthermore, Japanese Patent Laid-Open No. 10-70179 discloses a substrate holding device that reduces the influence of dust on the contacting surface for holding the substrate so as to readily remove dust in the case of dust attachment.
However, the substrate holding device disclosed in Japanese Patent Laid-Open No. 2004-140071 does not disclose any technique for specifying the type and position of the adsorption anomaly. Furthermore, in the device disclosed in Japanese Patent Laid-Open No. 10-70069 and Japanese Patent Laid-Open No. 10-70179, a special device is newly provided for the detection and removal of the adsorption anomaly.